Clunk noise! Need help..

[pbonsalb]

If it’s aluminum sounding it’s probably the driveshaft. Some say the M Variable diffs are noisy but I don’t know much. It is mentioned in a long diff thread. My car has always clunked. All stock, with stiffer subframe and diff bushings, with a CF driveshaft. I don’t worry about it.

[JetBlack_M3]

Originally Posted by G60nut

I'm also interested in in the out come. I noticed the same Aluminum bat noise when the drive train is loaded and unloaded during normal driving. I can also replicate the noise in the drive way at idle by holding the brakes and just slightly letting the clutch out in 1st then Reverse.

Check your CV joint. When it goes dry it tends to start making that sound. I'm switching out my driveshaft to a carbon one so I didn't bother fixing fix one

[G60nut]

Yea I would guess it would have something to do with the driveshaft biased on the noise. I've got a carbon shaft waiting to go in. I'm collecting parts to go through the rear of the car suspension wise, plan is everything from sub mounts to all adjustable rear links and ball joints to a new clutched LSD. After all my car only has 170k on the clock. I think it would be a good idea lol.

[bvrider1]

Hey OP,

Did you fix your issue w. the new drive shaft?

[JetBlack_M3]

Originally Posted by bvrider1

Hey OP,

Did you fix your issue w. the new drive shaft?

Got a new one piece carbon fiber driveshaft and clunk is still there lol. Just gonna ride it out till something breaks

Check your differential for any play, rear axles, make sure all suspension components are solid and tight, Center support bearing as it can cause clunk

[bvrider1]

Oh man that sucks. Was hoping you found a fix.

Originally Posted by JetBlack_M3

Got a new one piece carbon fiber driveshaft and clunk is still there lol. Just gonna ride it out till something breaks

Check your differential for any play, rear axles, make sure all suspension components are solid and tight, Center support bearing as it can cause clunk

[Bubbles]

Originally Posted by JetBlack_M3

Got a new one piece carbon fiber driveshaft and clunk is still there lol. Just gonna ride it out till something breaks

Check your differential for any play, rear axles, make sure all suspension components are solid and tight, Center support bearing as it can cause clunk

Check the half shafts for sticky cv joints.

[djsilverjohnson]

Does the M3 differential use a crush spacer/washer on the pinion? If the wheel hop caused enough peak loading on the diff to change the pinion depth it would increase gear lash and give slop between the pinion gear and ring gear.

[markchen888]

Hello Op, I have the exact same clunking noise, wondering if you have figured out the problem?

[JetBlack_M3]

Originally Posted by markchen888

Hello Op, I have the exact same clunking noise, wondering if you have figured out the problem?

I switched to purple poly mounts. Clunk went away for about a week or so then came back. Gave up on it at this point. Until something breaks, I’m not replacing anymore parts